Synapse-related protein alterations and estradiol deficiency associate with early Parkinsonism in female A53T-α-synuclein transgenic mice fed on a high-fat diet

Substantial evidence highlights the detrimental impact of a fat-rich diet on cognitive and emotional behaviour. Epidemiological studies have linked the consumption of saturated fat with an increased risk of Parkinson's disease (PD), whereas a low-fat or ketogenic diet is reported to improve both motor and non-motor symptoms. Several animal model studies further support these associations. However, the impact of a high-fat diet (HFD) on sex-specific behavioural alterations and the underlying molecular mechanism in PD remains poorly studied. In the present study, we investigated the impact of HFD on PD progression in a sex-specific manner using the A53T transgenic mouse model of PD. Behavioural and pathophysiological analyses revealed a faster onset and progression of PD-like phenotype in female mice exposed to HFD compared with the male mice. Proteomics profiling of brain tissues demonstrated positive enrichment of immune system-related pathways in males, while females exhibited considerable downregulation of synapse-associated pathways under HFD conditions. The reduced estradiol level was identified as a potential factor contributing to synaptic dysfunction and the subsequent early onset of PD in female mice. These findings provide novel insights into the sex-specific consequences of HFD on PD pathogenesis and highlight the role of estrogen-linked synaptic vulnerability in mediating diet-induced PD onset.